You can capture a loss by selling your shares in one company and buying shares in another similar company. It keeps us from being trapped. Keep in mind though, when we talk about a capital loss, it never deals with an IRA or a 401(k). There are rules to harvesting losses. You can use all of your losses, up to all of your gains, plus an additional $3,000. The losses never run out. From a tax stand point, if you file a joint 1040 it represents a spouse and spouse relationship. So if one spouse dies, half of those capital losses disappear.